The present invention relates to measuring devices and more particularly to a gauge for measuring both the depth and the diameter of a bore hole.
The measurement of single or multiple dimeters and depths of bore holes now accomplished with the use of telescope gauges, inside micrometers, dial bore gauges, calipers, digital micrometers and plug gauges often requires having to have different measuring instruments for each of the various diameters to be machined and inspected.
In the case of plug gauges and dial bore gauges, the narrow range of measurement of this type of tool requires the possession of a large inventory of plug gauges in incremental sizes for general machining and inspection work.
Telescope gauges and inside micrometers have a somewhat greater range, but are difficult to use in bore holes beyond the depth of the handles.
Telescope gauges and calipers have the additional disadvantage of inaccuracy due to the need for "feel" on the part of the machinist and inspector to estimate true size.
All of the instruments above were solely for the purpose of diameter measurements only.
The measurements of depths of each diameter is accomplished quite well by the use of vernier calipers, micrometer depth gauges and digital depth gauges, but this is accomplished separately from the measurement of diameters.
In practice, the measurement of bore holes of various close-tolerance diameters at various depths requires a multiplicity of tools and a significant expenditure of time in the location and use of these tools by both the machinist doing the work and the inspector who must verify the work done.